Roland Mathieu
The rise of high-entropy oxides as a major functional materials design principle in recent years has prompted us to investigate how compositional disorder affects long-range magnetic ordering in double perovskite oxides. Since ferromagnetic…
Dense systems of magnetic nanoparticles may exhibit dipolar collective behavior. However, two fundamental questions remain unsolved: i) whether the transition temperature may be affected by the particle anisotropy or it is essentially…
We present a combination of thermodynamic and dynamic experimental signatures of a disorder driven dynamic cooperative paramagnet in a 50% site diluted triangular lattice spin-1/2 system, Y$_2$CuTiO$_6$. Magnetic ordering and spin freezing…
Applications based on aggregates of magnetic nanoparticles are becoming increasingly widespread, ranging from hyperthermia to magnetic recording. However, although some uses require a collective behavior, other need a more individual-like…
Binary random compacts with different proportions of small (volume V) and large (volume 2V) bare maghemite nanoparticles (NPs) are used to investigate the effect of controllably broadening the particle size distribution on the magnetic…
Strong spin-orbit coupling (SOC) effects of heavy $d$-orbital elements have long been neglected in describing the ground states of their compounds thereby overlooking a variety of fascinating and yet unexplored magnetic and electronic…
STM based magnetotransport measurements of epitaxial La$_{0.7}$Sr$_{0.3}$MnO$_3$ 32 nm thick films with and without an internal LaMnO$_3$ layer (0-8 nm thick) grown on Nb doped SrTiO$_3$ are presented. The measurements reveal two types of…
X-ray diffraction, transmission electron microscopy, and magnetization measurements are employed to study the structural and magnetic properties of Mn-rich (Mn,Ga)As nanocrystals embedded in GaAs. These nanocomposites are obtained by…
We present a comprehensive study of the thickness dependence of static and magneto-dynamic magnetic properties of La$_{0.7}$Sr$_{0.3}$MnO$_3$. Epitaxial pulsed laser deposited La$_{0.7}$Sr$_{0.3}$MnO$_3$ / SrTiO$_3$(001) thin films in the…